Method for fabricating molded coil

ABSTRACT

There is provided a system for readily and efficiently fabricating a wound coil composed of a bobbinless coil. The system includes a coil winding device having an upper jig to which an upper plate is attached and a lower jig to which a lower plate is attached which are provided so as to be relatively displaceable and a tension device for applying predetermined tension to a wire rod fed from a wire rod supplying source. The coil winding device is provided with a claw section having first through third split claws that function as a winding section around which the wire rod is wound between the upper and lower plates and that slide in a radial direction when the upper jig is assembled coaxially with the lower jig.

CROSS REFERENCE TO RELATED APPLICATIONS

This application is a divisional of patent application Ser. No.12/230,505, filed on Aug. 29, 2008 (herein incorporated by reference),now U.S. Pat. No. 8,253,524 which claims the foreign priority benefitunder Title 35, United States Code, §119(a)-(d) of Japanese PatentApplication Nos. 2007-260860 and 2007-260861, filed on Oct. 4, 2007,2007-278948 and 2007-278949, filed on Oct. 26, 2007 and 2008-14550,filed on Jan. 25, 2008 in the Japan Patent Office, the disclosures ofwhich are herein incorporated by reference in their entirety.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a coil winding system for fabricating awound coil having a coil (solenoid) to be assembled into electromagneticdevices such as an electromagnetic valve and an electromagnetic actuatorfor example and to a method for fabricating a molded coil.

2. Description of Related Art

Heretofore, there have been known electromagnetic devices such as anelectromagnetic valve that actuates a valve by attracting a movable coreto a stationary core side by electromagnetic force generated by excitinga wound coil that composes a solenoid for example. Electrical insulation(isolation) of such electromagnetic devices has been maintained bycoating an outer surface of the wound coil by a resin material by meansof molding and the like.

Then, the present applicants have proposed a method of fabricating abobbinless coil assembly by integrally molding a coil cover (coilcoating member) made of a synthetic resin on an outer peripheral surfaceand both end surfaces in an axial direction, except of an inner surface,of a cylindrical bobbinless coil as shown in Japanese Patent ApplicationLaid-open No. 2007-67090.

The present invention has been made in connection with this proposal andgenerally seeks to provide a coil winding device capable of stablydisposing upper and lower plates above and under a claw section inpreferably obtaining a bobbinless wound coil.

The present invention also seeks to provide a coil winding methodcapable of readily forming a bobbinless coil by winding a wire rod andof steadily securing isolation of the wound coil and to provide thewound coil.

The invention also seeks to provide a method for molding a solenoid byresin capable of assuring a favorable fluidity by fully filling themolten resin into a cavity for forming a thin portion on an outer endsurface along an axial direction of a molded resin and to provide themolded resin.

The invention also seeks to provide a coil winding system that allowssuch a wound coil composed of the bobbinless coil to be readily andefficiently fabricated.

The invention primarily seeks to provide a method that allows a moldedcoil containing the wound coil composed of the bobbinless coil to bereadily and efficiently fabricated.

SUMMARY OF THE INVENTION

In order to attain the aforementioned objects, the invention provides acoil winding system for winding a coil as a wound coil, including a coilwinding device provided with an upper jig to which an upper plate isattached and a lower jig to which a lower plate is attached in such amanner that the upper and lower jigs are relatively displaceable, a wirerod supplying means for supplying a wire rod to be wound around the coilwinding device as the coil and a tension device for applyingpredetermined tension to the wire rod supplied to the coil windingdevice, wherein the coil winding device has a claw section as a wirewinding section around which the wire rod is wound between the upper andthe lower plates and the claw section contains a plurality of splitclaws that slide in a radial direction when the upper jig is assembledcoaxially with the lower jig.

According to the invention described above, the upper and lower platesare held while being separated by a predetermined distance when theupper jig to which the upper plate is attached is assembled with thelower jig to which the lower plate is attached by relatively displacingfrom each other. In succession, the wire rod is supplied from the wirerod supplying means to the coil winding device while applying thepredetermined tension to the wire by the tension device, so that thewire rod is wound around the wire winding section provided on aperipheral surface of the claw section of the coil winding device.

As a result, according to the invention, the wound coil composed of thebobbinless coil may be formed readily and efficiently by holding theupper and lower plates separated by the predetermined distance by theupper and lower jigs and by winding the wire rod around the wire windingsection on the peripheral surface of the claw section provided betweenthe upper and lower plate.

In this case, the wound coil has a stacked coil having the coil stackedinto a plurality of levels by the wire rod wound between the upper andlower plates and a weaving wire for holding the upper and lower platesby alternately weaving projections formed around an outer periphery ofthe upper and lower plates. Accordingly, the bobbinless coil in which nocylindrical coil bobbin is provided on the inner peripheral surface ofthe stacked coil may be held stably by the weaving wire withoutloosening the stacked coil.

Uniform holding force may be also generated in the peripheral directionby weaving the weaving wire around the side peripheral surface of thestacked coil and the uniform holding force can suitably hold the stackedcoil composed of the bobbinless coil.

Still more, the invention allows a molded coil to be formed throughsteps of forming the stacked coil having the coil stacked into aplurality of levels by winding the wire rod between the upper and lowerplates, forming the wound coil composed of the bobbinless coil byholding the upper and lower plates by the weaving wire by alternatelyweaving the projections formed around the outer periphery of the upperand lower plates and then loading the wound coil into a cavity of a dieassembly and coating the wound coil by molten resin.

Thus, the invention allows the molded coil containing the wound coilcomposed of the bobbinless coil to be readily and efficiently formed byimplementing the molding step of coating the wound coil by the moltenresin after forming the stacked coil and forming the wound coil byholding the upper and lower plates of the stacked coil by the weavingwire.

Accordingly, the invention provides the coil winding system that allowsthe wound coil composed of the bobbinless coil to be readily andefficiently fabricated. The invention also provides the method thatallows the molded coil containing the wound coil composed of thebobbinless coil to be readily and efficiently fabricated.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is an enlarged perspective view of a wound coil fabricated bymeans of a coil winding system according to an embodiment of theinvention;

FIG. 2 is a longitudinal section view of the wound coil shown in FIG. 1;

FIG. 3 is a plan view when an upper plate composing the wound coildescribed above is seen from above thereof;

FIG. 4 is a longitudinal section view of the wound coil seen along aline IV-IV in FIG. 1;

FIG. 5 is a bottom view showing an under surface of a lower platecomposing the wound coil;

FIG. 6 is a partially enlarged perspective view showing a guide slopeprovided on an upper surface of the lower plate;

FIG. 7 is a schematic structural perspective view of the coil windingsystem according to the embodiment of the invention;

FIG. 8 is a partially omitted exploded perspective view of a coilwinding device composing the coil winding system;

FIG. 9 is an exploded perspective view of the coil winding device;

FIG. 10 is an exploded perspective view of an upper jig composing thecoil winding device;

FIG. 11 is an exploded perspective view of a lower jig composing thecoil winding device;

FIG. 12 is a partially sectional plan view of the lower jig from whichan attachment plate is omitted;

FIG. 13 is a longitudinal section view showing a state before the upperjig is inserted into the lower jig;

FIG. 14 is a longitudinal section view showing a state during when theupper jig is inserted into the lower jig;

FIG. 15 is a longitudinal section view showing a state after when theupper jig has been inserted into the lower jig;

FIG. 16 is an enlarged longitudinal section view of a region denoted bya reference character P in FIG. 15;

FIG. 17 is an enlarged longitudinal section view of a region denoted bya reference character Q in FIG. 15;

FIG. 18 shows a state laid out in a peripheral direction in which a wirerod is wound around claws;

FIGS. 19A through 19C are partially omitted perspective views showing asequence how the wire rod is wound around the claw section providedbetween the upper and lower plates;

FIG. 20 is a partially cut-away side view showing a state when the wirerod is wound around first through third split claws composing the clawsection by representing peripheral faces of the first through thirdsplit claws in flat for convenience sake;

FIG. 21 is a partially longitudinal section view showing a state inwhich the wire rod is folded back and is stacked;

FIG. 22 is a perspective view showing states of weaving circular arcprojections formed respectively around an outer peripheral portion ofthe upper and lower plates by a weaving wire in an elapsed time-seriesmanner;

FIG. 23 is a schematic structural longitudinal section view of a dieassembly for carrying out a method of molding the wound coil;

FIG. 24 is a schematic structural longitudinal section view of the dieassembly shown in FIG. 23 that is clamped after loading aform-to-be-molded into a cavity of the assembly;

FIG. 25 is a schematic structural longitudinal section view of the dieassembly in a state of injecting molten resin from gates in the clampedstate;

FIG. 26 is a schematic structural longitudinal section view of the dieassembly opened to take out the molded resin;

FIG. 27 is a plan view of the die assembly showing positionalrelationship among the projections and the gates of a first plate;

FIG. 28 is a partially enlarged longitudinal section view showing astate in which a flow of the molten resin injected from the gate to athin molding airspace portion is urged by the projection;

FIG. 29A is a perspective view showing the coil-to-be-molded and FIG.29B shows a perspective view of the molded resin; and

FIG. 30 is a block diagram showing steps of fabricating the molded coil.

PREFERRED EMBODIMENTS OF THE INVENTION

Next, preferred embodiments of the invention will be explained belowwith reference to the appended drawings. FIG. 1 is an enlargedperspective view of a wound coil fabricated by means of a coil windingsystem according to an embodiment of the present invention, FIG. 2 is alongitudinal section view of the wound coil shown in FIG. 1, FIG. 3 is aplan view when an upper plate composing the wound coil described aboveis seen from above thereof, FIG. 4 is a longitudinal section view of thewound coil seen a line IV-IV in FIG. 1, FIG. 5 is a bottom view showingan under surface of a lower plate composing the wound coil, FIG. 6 is apartially enlarged perspective view showing a guide slope provided on anupper surface of the lower plate and FIG. 7 is a schematic structuralperspective view of the coil winding system according to the embodimentof the invention.

At first, the wound coil 100 in which a wire rod 106 is wound by meansof the coil winding system 10 shown in FIG. 7 will be explained. It isnoted that in a step of winding the wire rod 106 described below, anaxial direction will be defined as a column direction of the wire rod106 and a radial direction as a level direction.

As shown in FIGS. 1 and 2, the wound coil 100 includes an upper plate102 (the upper plate 102 has an upper surface 102 a and an under surface102 b) made of a resin material and having a through hole 101 throughwhich an upper jig 12 of the coil winding system 10 is inserted and alower plate 104 (the lower plate 104 has an upper surface 104 a and anunder surface 104 b) made of a resin material and having a through hole103.

The wound coil 100 also includes a stacked coil 108 having a coil formedby winding and stacking a wire rod (conductive wire) into a plurality oflevels and by sandwiching between the upper and lower plates 102 and104, and a weaving wire 116 for holding the upper and lower plates 102and 104 by alternately weaving circular arc projections 114 a and 114 bof the upper and lower plates 102 and 104 disposed in zigzag withoutbeing superimposed in a vertical direction. It is noted that no coremember such as a coil bobbin is provided within a coil inner peripheralsurface 120 of the stacked coil 108 and the surface 120 is exposed tothe outside.

The circular arc projections 114 a and 114 b protruding in a radialoutward direction from the outer peripheral portions of the upper andlower plates 102 and 104 have first guide grooves 122 formed so as toguide the weaving wire 116 in weaving the weaving wire 116 (see FIGS. 3and 5). As shown in FIG. 4, a bottom inner wall of the first guidegroove 122 is formed so as to have a curved face 123 whose center partis slightly raised when seen longitudinally in section, so that theweaving wire 116 may be readily woven to the circular arc projections114 a and 114 b and the weaving wire 116 is kept to have adequatetensile force.

It is noted that the circular arc projections 114 a are provided at fiveplaces of the upper plate 102 (see FIG. 3) and the circular arcprojections 114 b are provided at six places of the lower plate 104 (seeFIG. 5). The first guide groove 122 provided on the circular arcprojection 114 a of the upper plate 102 is formed so as to open upwardand the first guide groove 122 provided on the circular arc projection114 b of the lower plate 104 is formed so as to open downwardrespectively to suitably hold the weaving wire 116.

As shown in FIG. 1, the upper surface 102 a of the upper plate 102 isprovided with a pin hole 119 a into which a first pin 17 a of the upperjig 12 described later (see FIGS. 9 and 10) is inserted to position theupper plate 102 at predetermined position with respect to the upper jig12 by inserting the first pin 17 a into the pin hole 119 a.

Further, as shown in FIG. 5, the under surface 104 b of the lower plate104 is provided with a pin hole 119 b into which a second pin 17 b ofthe lower jig 14 described later (see FIGS. 9 and 11) is inserted toposition the lower plate 104 at predetermined position with respect tothe lower jig 14 by inserting the second pin 17 b into the pin hole 119b. It is noted that the pin holes 119 a and 119 b are formed so as notpenetrate through the upper plate 102 or the lower plate 104 and so asto close on their way. It suitably prevents an outer surface of thestacked coil 108 sandwiched between the upper and lower plates 102 and104 from being damaged.

As shown in FIG. 5, the lower plate 104 is provided with a first windingsecuring section 110 a having substantially a shape of L in transversesection and protruding in the radial outward direction to wind andsecure a winding beginning portion of the wire rod 106 and a secondwinding securing section 110 b having substantially a shape of L intransverse section to wind and secure a winding ending portion of thewire rod 106. It is noted that the first and second winding securingsections 110 a and 110 b are caulked respectively with a pair ofterminals 152 a and 152 b (see FIG. 29) in a next process toelectrically connect the winding beginning portion of the wire rod 106with the winding ending portion thereof.

Further, as shown in FIG. 5, a rectangular plate portion 124 isintegrally formed between the outer peripheral surface of the lowerplate 104 and the first and second winding securing sections 110 a and110 b. The plate portion 124 of the under surface 104 b of the lowerplate 104 is provided with a curved second guide groove 126 formed so asto guide the winding beginning portion of the wire rod 106 secured tothe first winding securing section 110 a from the first winding securingsection 110 a toward an outer peripheral part of the lower plate 104.

Still more, as shown in FIGS. 2, 5 and 6, an inner peripheral portion ofthe lower plate 104 is provided with a cylindrical projection 128 formedso as to slightly extend in the axial direction (at the upper and lowerfaces 104 a and 104 b of the lower plate 104). Further, as shown in FIG.6, the upper surface 104 a of the lower plate 104 is provided with aguide slope 130 formed as a concave groove in section that extends in atangent direction of the cylindrical projection 128 to guide the windingbeginning portion of the wire rod 106 from the outer peripheral portionof the lower plate 104 to the inner peripheral portion thereof. As shownin FIG. 20, the guide slope 130 is formed so as to have a slope (groovebottom) inclined by a predetermined angle so that a depth thereof isshallow on the inner peripheral side and is gradually deepened on theouter peripheral side.

One side wall 132 of the guide slope 130 substantially orthogonal to theslope described above is provided with two ribs 134 for example whichare separated by a predetermined distance and bulge in a horizontaldirection toward the slope as shown in FIG. 6. These ribs 134 abut thewire rod 106 guided along the guide slope 130 to block molten resin frombeing filled into the guide slope 130 along the wire rod 106 when thewound coil is molded in the following process. As a result, it becomespossible to suitably prevent the molten resin from entering the coilinner peripheral surface 120. It is noted that the number of the ribs134 is not limited to be a plural number and may be one or more.

Still more, as shown in FIG. 5, the circular arc projection 114 b of thelower plate 104 is provided with a notch 136 formed so as to anchor aweaving beginning portion of the weaving wire 116 and the other circulararc projection 114 b is provided with another notch 136 formed so as toanchor a weaving ending portion of the weaving wire 116.

As shown in FIG. 21, the under surface 102 b of the upper plate 102facing the lower plate 104 is provided with third guide grooves 138,i.e., a plurality of grooves each having a circular arc in longitudinalsection juncturally formed. The third guide groove 138 exhibits itsfunction of guiding and aligning the wire rod 106 when the wire rod 106is folded and is laminated into a plurality of levels.

Next, the coil winding system 10 of the present embodiment will beexplained with reference to FIGS. 7 and 8. FIG. 8 is a partially omittedexploded perspective view of a coil winding device composing the coilwinding system.

This coil winding system 10 includes a coil winding device 15 composedof the upper jig 12 provided liftably along the vertical direction bymeans of an elevation mechanism not shown and a lower jig 14 supportedon a base not shown rotatably along a direction of an arrow under arotating and driving action of a motor M.

The coil winding system 10 also includes a nozzle 30 for feeding thewire rod 106 supplied from a wire rod supplying source 17 to the coilwinding device 15, a triaxial actuator mechanism 32 composed of aplurality of assembled linear actuators to displace the nozzle 30 intriaxial directions of XYZ orthogonal from each other under a guidingaction of a guide rail not shown and a tension device 34 for applying anadequate tension to the wire rod 106 fed from the nozzle 30. It is notedthat the nozzle 30, the triaxial actuator mechanism 32 and the wire rodsupplying source 17 function as a wire rod feeding means.

FIG. 9 is an exploded perspective view of the coil winding device, FIG.10 is an exploded perspective view of the upper jig composing the coilwinding device, FIG. 11 is an exploded perspective view of the lower jigcomposing the coil winding device and FIG. 12 is a partially sectionalplan view of the lower jig from which an attachment plate is omitted. Asshown in FIGS. 9 and 10, the upper jig 12 is composed of a upper jigbody 210 for attaching and latching the upper plate 102 and a taperedportion 220 that is inserted into an opening of a claw section 240 ofthe lower jig 14 described later to expand the claw section 240 (splitclaws).

As shown in FIG. 10, the upper jig body 210 has a thick disk-likeattachment seat 211 having a attachment surface 211 a (see FIGS. 13through 15) formed so as to accommodate the upper surface 102 a of theupper plate 102 and a insertion rod portion 215 extending downwardperpendicularly from a center of the attachment seat 211.

The attachment seat 211 is liftably linked by means of the elevationmechanism not shown, is provided with the attachment surface 211 a thatabuts the upper surface 102 a of the upper plate 102 at the undersurface thereof and is provided with the first pin 17 a protrudingdownward to relatively position the upper plate 102 fitted to theattaching surface 211 a. It is noted that the upper plate 102 isattached to the attaching surface 211 a of the attachment seat 211 bymeans of opening claws 213 (see FIG. 13) that open in the radialdirection.

The insertion rod portion 215 is substantially a cylindrical column tobe inserted into the claw section 240 of the lower jig 14 describedlater and has a ringed tapered surface 216 at a lower end thereof formedso as to be readily inserted.

The insertion rod portion 215 is also provided with a key groove 217formed at the lower part thereof along the perpendicular direction sothat a key 231 (see FIGS. 14 and 15) provided in the lower jig 14 is tobe inserted therein. Thereby, relative position in the peripheraldirection of the insertion rod portion 215 (the upper jig 12) and thelower jig 14 is determined.

Still more, the insertion rod portion 215 is provided with a lockinggroove 218 around the lower part thereof so that a locking piece 232 ofthe lower jig 14 is inserted into the locking groove 218 when the upperjig 12 is inserted into the lower jig 14 (see FIG. 15). It prevents theupper jig 12 from slipping out after inserting the upper jig 12 into thelower jig 14. It is noted that the locking piece 232 is provided with acylinder not shown at an underside thereof and the locked state isreleased when a piston rod of the cylinder presses a lower part of thelocking piece 232 and the locking piece 232 separates from the lockinggroove 218.

The tapered portion 220 is formed substantially into an invertedtruncated cone so as to be inserted into the claw section 240 insuccession after inserting the lower part of the insertion rod portion215 into the claw section 240 and has a tapered surface 221 around asurface thereof. The tapered portion 220 is provided with an insertionhole 222 that penetrates through the tapered portion 220 in the axialdirection and the insertion rod portion 215 is inserted through theinsertion hole 222.

There are also provided with two threaded rods 223 above the taperedportion 220. The two threaded rods 223 are to be screwed into the twoscrew holes 214 of the attachment seat 211. They are arranged such thatposition of lower ends of the two threaded rods 223 may be controlled byfastening nuts 224 to upper ends of the respective threaded rods 223 andby locking the nuts 224 to the attachment seat 211.

The lower ends of the threaded rods 223 butt an upper surface of thetapered portion 220, so that the tapered portion 220 is set atpredetermined level controlled by height of the threaded rods 223 withrespect to the attachment seat 211. It is noted that a key not shownguides the tapered portion 220 with respect to the body 210 of the upperjig in the perpendicular direction and holds the tapered portion 220 soas not to slip out of the body 210.

A compression coil spring 225 is interposed between the tapered portion220 and the attachment seat 211 so that the tapered surface 221 of thetapered portion 220 suitably butts the tapered surface 240 a of the clawsection 240 (see FIG. 13) when the upper jig 12 is inserted into theclaw section 240.

As shown in FIGS. 8 and 11, the lower jig 14 has a substantiallycylindrical body 230 of the lower jig, a pedestal 230 a provided on thelower jig body 230 described above and is composed of a flange whosediameter is enlarged, a ringed plate 261 inserted within a circularconcave portion formed in the pedestal 230 a, the claw section 240having the first through third split claws 241 a through 241 cdisplaceably supported along the radial direction of the ringed plate261 and whose diameter is enlarged along the radial outward directionwhen the tapered portion 220 of the upper jig 12 is inserted and a pairof latching sections 212 that protrude in directions orthogonal to anaxial line of the lower jig body 230 for latching one winding startingend portion of the wire rod 106 and the weaving wire 116.

The lower jig 14 also has three radial springs 251 that press the firstthrough third split claws 241 a through 241 c of the claw section 240 inradial inner directions by their spring force and six thrust springs 265that press the claw section 240 upward by their spring force as shown inFIG. 11.

The lower jig body 230 is arranged so that it is appropriately rotatedby the motor M. The lower jig body 230 is provided with the key 231 thatis inserted into the key groove 217 of the upper jig 12 and the lockingpiece 232 that engages with the locking groove 218 of the upper jig 12(see FIG. 15).

FIGS. 13, 14 and 15 are longitudinal section views showing states beforethe upper jig is inserted into the lower jig, during when the upper jigis inserted into the lower jig and after when the upper jig has beeninserted into the lower jig. Although the claw section 240 iscylindrical when it is closed, it has the first through third splitclaws 241 a through 241 c whose horizontal section is circular arc whenit is split in the peripheral direction. Each of the first through thirdsplit claws 241 a through 241 c is arranged to be slidable along theradial direction and is pressed toward the radial inner direction by theradial spring 251.

That is, when the upper jig 12 is not inserted into the claw section240, each of the first through third split claws 241 a through 241 c ispressed toward the radial inner direction by the spring force of theradial spring 251 and the claw section 240 is closed like a cylinderwith its diameter reduced. When the upper jig 12 is inserted into theclaw section 240 on the other hand, each of the first through thirdsplit claws 241 a through 241 c is displaced in the radial outerdirection by going against the spring force o f the radial spring 251and the claw section 240 is opened with its diameter enlarged.

An inner peripheral surface of each of the first through third splitclaws 241 a through 241 c is formed to be a tapered surface 240 a whosediameter is gradually reduced on the lower side as shown in FIG. 13. Aninner peripheral surface 240 b whose inner diameter is constant isformed below the tapered surface 240 a.

Each of the first through third split claws 241 a through 241 c isprovided with a peripheral groove 242 along the peripheral direction onthe lower side of the outer peripheral surface thereof as shown in FIG.11. A narrow and constricted peripheral groove 242 is also provided atthe part where the peripheral groove 242 of each of the first throughthird split claws 241 a through 241 c is formed such that a pair ofprotrusions 252 a of a guide member 252 described later slidably pinchthe neck portion 247. The neck portion 247 is also provided with aspring hole 242 a by an outer side face thereof so that the radialspring 251 is fitted into the spring hole 242 a to position the guidemember 252.

Each of the first through third split claws 241 a through 241 c isprovided with a first stepped portion 243 that extends in the peripheraldirection on an upper part of the outer peripheral surface thereof and asecond stepped portion 244 that extends in the peripheral direction on alower part of the outer peripheral surface thereof. The first and secondstepped portions 243 and 244 are provided respectively at positionsseparated by a predetermined distance along the axial direction of theclaw section 240. Here, the first stepped portion 243 is arranged so asto butt an inner lower face 140 of the upper plate 102 as shown in FIG.16 and the second stepped portion 244 is arranged so as to butt an innerupper surface 142 of the lower plate 104 as shown in FIG. 17,respectively, when the claw section 240 is opened. FIGS. 16 and 17 areenlarged longitudinal section views of regions denoted by referencecharacters P and Q, respectively, in FIG. 15.

Each of the first through third split claws 241 a through 241 c isprovided with a latching flange 245 formed into a circular arc when seenhorizontally in section at the lower end portion thereof. The latchingflange 245 is arranged so as to be latched by a raised portion 262 ofthe ringed plate 261 when the claw section 240 is closed (see FIG. 13).

As shown in FIG. 7, a peripheral surface of the claw section 240 thatfunctions as a wired section to be wound by the wire rod 106 is providedso as to be exposed between the upper and lower plates 102 and 104separated by the predetermined distance along the vertical directionwhen the upper jig 12 is coaxially assembled with the lower jig 14. Thisperipheral surface of the claw section 240 is formed by the peripheralsurfaces of the first through third split claws 241 a through 241 cseparated with clearances of a predetermined angle in the peripheraldirection.

Here, a plurality of chases 246 that extends in parallel along thehorizontal direction and that guides the wire rod 106 wound around theperipheral surface is formed around the peripheral surface of the firstand second split claws 241 a and 241 b as shown in FIG. 18. Theperipheral surface of the third split claw 241 c is a smoothly-shapedflat surface 248 around which no irregularity is formed. Thissmoothly-shaped flat surface 248 achieves a smooth shift of the wire rod106 wound around the peripheral surface in transferring to a next row.

As shown in FIG. 12, the three radial springs 251 are arranged so as tobe attached on the upper surface of the pedestal 230 a of the lower jigbody 230 through the guide members 252, when seen horizontally, by beingseparated equiangularly (every 120°) in the peripheral direction and tobe guided along the radial direction by the guide members 252.

The guide member 252 is provided, at one end portion thereof along theaxial direction, with the pair of protrusions 252 a that protrudesubstantially in parallel toward the first through third split claws 241a through 241 c. The pair of protrusions 252 a is arranged so as to beinserted into the peripheral groove 242 of each of the first throughthird split claws 241 a through 241 c and to slidably sandwich the neckportion 247 of each of the first through third split claws 241 a through241 c. Thereby, each of the first through third split claws 241 athrough 241 c is provided slidably on the upper part of the lower jigbody 230 along the radial direction.

As shown in FIG. 11, a ringed attachment plate 253 on which the lowerplate 104 is fitted is fixed on the guide member 252. This attachmentplate 253 is provided, on an upper surface thereof, with a second pin 17b for positioning the lower plate 104 at predetermined position withrespect to the lower jig 14 and with rectangular concave portions 254into which the guide members 252 are fitted.

As shown in FIG. 12, the six thrust springs 265 are compression coilsprings for example and are arranged so as to be fitted into springholes formed within the circular concave portion of the pedestal 230 aof the lower jig body 230 and so as to be separated equiangularly (every60°) along the peripheral direction.

As shown in FIGS. 11 and 13, the ringed plate 261 is disposed on and isuniformly supported by the six thrust springs 265. The claw section 240is disposed on the upper surface of the ringed plate 261. That is, thesix thrust springs 265 are arranged so as to press the claw section 240upward through the ringed plate 261.

The ringed plate 261 is provided, at an inner peripheral portionthereof, with the raised portion 262 thickly formed as compared to anouter peripheral portion thereof. That is, the raised portion 262 isprovided so that it butts and latches the latching flange 245 of each ofthe first through third split claws 241 a through 241 c when the upperjig 12 is not inserted into the claw section 240 and the claw section240 is closed. That is, the raised portion 262 functions as a stopperfor controlling the displacement of the first through third split claws241 a through 241 c in the radial inner direction when the claw section240 is closed.

The coil winding system 10 of the present embodiment is constructedbasically as described above. Next, operations of the coil windingsystem 10 will be explained below.

A preliminary process carried out before winding the wire rod 106 willbe briefly explained at first. The upper jig 12 attached with the upperplate 102 and coaxially separated from the lower jig 14 attached withthe lower plate 104 as shown in FIG. 8 is lowered toward the lower jig14 by means of the elevation mechanism not shown to assemble the upperjig 12 with the lower jig 14.

Here, the tapered portion 220 of the upper jig 12 is inserted into theclaw section 240 and presses the first through third split claws 241 athrough 241 c in the radial outward direction. Then, the first throughthird split claws 241 a through 241 c slide in the radial outwarddirection and the upper jig 12 is assembled with the lower jig 14. Whenthe upper and lower jigs 12 and 14 are assembled, the upper and lowerplates 102 and 104 are held while separating from each other by apredetermined distance. Thus, the preliminary process for winding thewire rod 106 around the peripheral surface (wound section) of the clawsection 240 is completed.

Operations for assembling the upper jig 12 with the lower jig 14 will beexplained in detail below with reference to FIGS. 13 through 17.

As shown in FIG. 13, the upper plate 102 is attached to the undersurface (the attaching surface 211 a) of the attachment seat 211 of theupper jig 12 while aligning the first pin 17 a with the pin hole 119 a.Meanwhile, the lower plate 104 is attached to the upper surface 253 a ofthe attachment plate 253 of the lower jig 14 while aligning the secondpin 17 b with the pin hole 119 b.

After attaching the upper and lower plates 102 and 104 respectively tothe upper and lower jigs 12 and 14, the upper jig 12 is lowered by theelevation mechanism not shown while aligning the key 231 of the lowerjig 14 with the key groove 217 of the upper jig 12 to insert theinsertion rod portion 215 of the upper jig 12 into the opening of theclaw section 240 of the lower jig 14.

When the insertion rod portion 215 butts the inner peripheral surface240 b of the first through third split claws 241 a through 241 c afterthat, the claw section 240 starts open because the first through thirdsplit claws 241 a through 241 c slide in the radial outward direction bygoing against the spring force of the radial spring 251.

When the tapered surface 221 of the tapered portion 220 is loweredfurther while butting the tapered surface 240 a of the first throughthird split claws 241 a through 241 c, each of the first through thirdsplit claws 241 a through 241 c slides further in the radial outwarddirection. Then, when the latching flange 245 of each of the firstthrough third split claws 241 a through 241 c butts an inner peripheralsurface 253 b of the attachment plate 253 as shown in FIG. 15, thesliding movement of each of the first through third split claws 241 athrough 241 c in the radial outward direction is restricted.

Here, the first through third split claws 241 a through 241 c arepressed by the respective thrust springs 265 through the ringed plate261, so that they may be pressed upward uniformly and a gap G is createdbetween the second stepped portion 244 on the lower side of the firstthrough third split claws 241 a through 241 c and the inner peripheralupper end surface 142 of the lower plate 104 as shown in FIGS. 13 and14.

When the upper jig 12 is lowered further and the under surface 261 a ofthe ringed plate 261 butts the upper surface 230 a of the lower jig body230, the upper jig 12 stops from being lowered. At this time, each ofthe first through third split claws 241 a through 241 c slides downwardalong with the lowering movement of the upper jig 12 by going againstthe pressing force of each thrust spring 265.

Here, the inner peripheral lower end surface 140 of the upper plate 102butts the first stepped portion 243 on the upper side of the firstthrough third split claws 241 a through 241 c as shown in FIG. 16 in theupper region P of the first through third split claws 241 a through 241c. Meanwhile, the inner peripheral upper end surface 142 of the lowerplate 104 butts the second stepped portion 244 on the lower side of thefirst through third split claws 241 a through 241 c as shown in FIG. 17in the lower region Q of the first through third split claws 241 athrough 241 c.

Specifically, because each of the first through third split claws 241 athrough 241 c is pressed upward in advance by the spring force of thethrust spring 265 and the gap G is created as shown in FIGS. 13 and 14,the second stepped portion 244 on the lower side butts the innerperipheral upper end surface 142 of the lower plate 104 after when theinner peripheral upper end surface 142 of the lower plate 104 ispositioned right under the second stepped portion 244 of the lower sideof each of the first through third split claws 241 a through 241 c inthe lower region Q.

As a result, it becomes possible to prevent such a trouble that an outerperipheral surface of a split claw not shown that has no thrust spring265 and slides only in the radial outward direction otherwise butts aninner peripheral surface 103 a of the lower plate 104 (see FIG. 17) forexample.

Thus the upper jig 12 is coaxially assembled with the lower jig 14 andis locked by the locking piece 232 of the lower jig 14 that engages withthe locking groove 218.

In the state when the upper jig 12 is thus assembled with the lower jig14, an axial length L between the under surface (the attaching surface211 a) of the attachment seat 211 in the upper jig 12 and the uppersurface 253 a of the attachment plate 253 in the lower jig 14 is at apredetermined value as shown in FIG. 15. Position of enlarged outerperiphery of each of the first through third split claws 241 a through241 c, i.e., a radial length D, is also set at a predetermined value.

Here, respective levels in the axial direction of the first steppedportion 243 formed on the upper side and of the second stepped portion244 formed on the lower side of the first through third split claws 241a through 241 c are set at position where compression load is appliedrespectively by the inner peripheral lower end surface 140 of the upperplate 102 and the inner peripheral upper end surface 142 of the lowerplate 104.

As a result, the upper plate 102 is sandwiched at the predeterminedposition, i.e., restrained, between the under surface (the attachingsurface 211 a) of the attachment seat 211 and the first stepped portion243 of the first through third split claws 241 a through 241 c and thelower plate 104 is restrained between the upper surface 253 a of theattachment plate 253 and the second stepped portion 244 of the firstthrough third split claws 241 a through 241 c.

More specifically, the upper plate 102 receives pressure A2 thatperpendicularly presses down the upper surface of the upper plate 102from the under surface (the attaching surface 211 a) of the attachmentseat 211 (see FIG. 15) and in the same time, receives a compression load(pressure A3: see FIGS. 15 and 16) that presses the inner peripherallower end surface 140 of the upper plate 102 upward in the axialdirection from the first stepped portion 243 of the first through thirdsplit claws 241 a through 241 c.

Still more, the lower plate 104 receives pressure A6 thatperpendicularly presses up the under surface of the lower plate 104 fromthe upper surface 253 a of the attachment plate 253 (see FIG. 15) and inthe same time, receives a compression load (pressure A5: see FIGS. 15and 17) that presses the inner peripheral upper end surface 142 of thelower plate 104 downward in the axial direction from the second steppedportion 244 of the first through third split claws 241 a through 241 c.Then, a predetermined clearance is formed between the first throughthird split claws 241 a through 241 c and the through hole 103 of thelower plate 104 as shown in FIG. 17.

In the state in which the upper jig 12 is thus assembled with the lowerjig 14, the upper and lower plates 102 and 104 are restrained at thepredetermined position with respect to the opened claw section 240 andthe distance between the upper and lower plates 102 and 104 is set at apredetermined width.

In other words, because the outer peripheral surface of the claw section240 becomes a core, the upper plate 102 becomes an upper flange and thelower plate 104 becomes a lower flange, it becomes possible to form astructure similar to a bobbin having upper and lower flanges, i.e., animaginary bobbin, and to readily wind the wire rod 106. Thereby, itbecomes possible to wind the wire rod 106 neatly between the upper andlower plates 102 and 104 and to obtain the stacked coil 108 whosewinding formation is not distorted, i.e., in which the wire rods 106 arewell arrayed in the axial direction.

In succession, a method for winding the wire rod 106 between the upperand lower plates 102 and 104 held by the upper and lower jigs 12 and 14as described above will be explained. FIG. 18 shows a state laid out inthe peripheral direction in which the wire rod is wound around claws,FIGS. 19A through 19C are partially omitted perspective views showing asequence how the wire rod is wound around the claw section providedbetween the upper and lower plates and FIG. 20 is a partially cut-awayside view showing a state when the wire rod is wound around the firstthrough third split claws composing the claw section by representingperipheral surfaces of the first through third split claws in flat forconvenience sake.

First, in the state in which the motor M is powerless and the upper andlower jigs 12 and 14 coaxially assembled are at rest, the nozzle 30 isdisplaced under the driving action of the triaxial actuator mechanism 32to latch one winding starting end of the wire rod 106 fed from thenozzle 30 to the latching section 212 of the lower jig body 230. Then,as shown in FIG. 19A, the wire rod 106 is wound once around an outerperipheral surface of a first winding securing section 110 a provided onthe left side of the lower plate 104 from the lower side thereofclockwise as shown by arrows a1 and a2 in the figure. It is noted thatthe wire rod 106 fed from the nozzle 30 is tensioned adequately by thetension device 34, so that it is possible to suitably prevent the woundwire rod 106 from becoming loose.

Next, the nozzle 30 is displaced along the horizontal direction underthe driving action of the triaxial actuator mechanism 32 to insert thewire rod 106 along a second guide groove 126 formed at an under surfaceof a second winding securing section 110 b on the right side of thelower plate 104 as shown in a partial perspective view in FIG. 19A.Then, the wire rod 106 is guided from the outer peripheral portion tothe inner peripheral portion of the lower plate 104 so that it is guidedalong the guide slope 130 formed on the upper surface 104 a of the lowerplate 104.

When the wire rod 106 is guided along the slope of the guide slope 130and reaches a lowest part of the flat surface 248 of the third splitclaw 241 c, the motor M is actuated to rotate the upper and lower jigs12 and 14 integrally in a direction of an arrow A. Thereby, the wire rod106 is guided by the groove 246 of the first and second split claws 241a and 241 b and reaches again the flat surface 248 of the third splitclaw 241 c as shown in FIG. 20. At this time, because the peripheralsurface of the third split claw 241 c is formed by the flat surface 248and does not restrain the winding direction of the wire rod 106 at all,it can shift the wire rod 106 to a next row smoothly.

The nozzle 30 is also displaced upward and the wire rod 106 is wound byplural times along the direction of rows of the peripheral surfaces ofthe first through third split claws 241 a through 241 c (axialdirection) as indicated by an arrow a4 (see FIG. 19B). Because thenozzle 30 reciprocates along the axial direction, the wire rod 106 issequentially laminated in the radial direction of the peripheral surfaceof the claw section 240 as shown in FIG. 19 c.

After forming the stacked coil 108 composed of a plurality of levels ofthe wire rod 106 fed by rotating the upper and lower jigs 12 and 14 in abody and reciprocating the nozzle 30 by a plurality of times between thelower plate 104 and the upper plate 102, the winding ending portion ofthe wire rod 106 is guided from the inner peripheral portion to theouter peripheral portion of the upper surface 104 a of the lower plate104 and is wound once an outer peripheral surface of the second windingsecuring section 110 b on the right side of the lower plate 104 fromabove clockwise as indicated by arrows a5 through a7 in FIG. 19C in thestate when the rotation of the upper and lower jigs 12 and 14 isstopped. Then, the winding ending portion of the wire rod 106 is cut bya cutter means not shown.

Thus, in the state in which the upper and lower jigs 12 and 14 arecoaxially assembled and the upper and lower plates 102 and 104 areseparated by the predetermined distance on the claw section 240, thestacked coil 108 in which the wire rod 106 is neatly wound and isarrayed in the axial direction may be obtained between the upper andlower plates 102 and 104 that are set to have the predetermined width(see a block E in FIG. 30).

Still more, because the winding beginning and ending portions of thestacked coil 108 exposed to the outside are secured respectively by theadjoining first and second winding securing sections 110 a and 110 b andare disposed in cross by being separated respectively at the upper andlower surfaces of the plate portion 124 of the lower plate 104, itbecomes possible to secure isolation quality of the stacked coil 108including the winding beginning and ending portions.

Next, a method for weaving the weaving wire 116 for vertically holdingthe stacked coil 108 composed of the bobbinless coil will be explainedbelow with reference to FIG. 22. It is noted that how one weavingbeginning end of the weaving wire 116 is secured to the latching section212 is the same with the case of forming the stacked coil 108 by windingthe wire rod 106, its explanation will be omitted here. Still more,although the following explanation will be made by using the wire rod106 (conductive line) fed from the nozzle 30, the invention is notlimited to that and another wire rod beside the conductive line may beused.

As indicated by arrows c1 through c3 in FIG. 22, the weaving beginningportion of the weaving wire 116 is wound once around the outerperipheral surface of the circular arc projection 114 b of the lowerplate 104 from the lower side clockwise and then the weaving wire 116 isengaged with the first guide groove 122 (see FIG. 3) of the circular arcprojection 114 a of the upper plate 102. Because the circular arcprojection 114 b of the lower plate 104 is provided with a notch portion136 formed so as to secure the weaving beginning portion of the weavingwire 116, the notch portion 136 smoothly secures the weaving beginningportion of the weaving wire 116 at this time.

Next, the weaving wire 116 is woven sequentially along the first guidegroove 122 of the circular arc projection 114 b of the lower plate 104and the first guide groove 122 of the circular arc projection 114 b ofthe upper plate 102 that are disposed alternately along the peripheraldirection so as not to be superimposed in the vertical direction asindicated by arrows c4 through c17 while reciprocating the nozzle 30 inthe vertical direction in the state in which the upper and lower jigs 12and 14 are rotated in a body along the peripheral direction under thedriving action of the motor M. It is noted that the motor M iscontrolled by a controller not shown and is normally and inverselyrotated appropriately to adequately tension the weaving wire 116 wovenalong the circular arc projections 114 a and 114 b of the upper andlower plates 102 and 104.

Here, because the circular arc projection 114 a of the upper plate 102and the circular arc projection 114 b of the lower plate 104, i.e., theportions where the weaving wire 116 engages, are disposed alternatelyfrom each other in zigzag in the peripheral direction, it is possible tosuitably prevent the upper and lower plates 102 and 104 from beingdislocated with respect to the rotating direction thereof.

The weaving wire 116 woven between the upper and lower plates 102 and104 extends substantially in parallel with the axial direction of thestacked coil 108. Therefore, it is possible to obtain a good moldedresin (see FIG. 29A) while maintaining the state of the stacked coil 108held by the weaving wire 116 in molding the outer surface of the woundcoil 100 by molten resin in a next process for example because themolten resin applies no excessive load to the weaving wire 116 bysetting directions for filling the molten resin injected from gates of adie assembly described later.

After weaving the circular arc projections 114 a and 114 b of the upperand lower plates 102 and 104 by the weaving wire 116 alternately alongthe vertical direction, drawing the weaving wire 116 along theperipheral direction of the upper and lower plates 102 and 104 andwinding the weaving wire 116 once around an outer peripheral surface ofanother circular arc projection clockwise as indicated by arrows c18through c20, the weaving ending portion of the weaving wire 116 is cutby the cutter means not shown. At this time, because the other circulararc projection of the lower plate 104 is provided with the notch portion136 formed so as to secure the weaving ending portion of the weavingwire 116, the notch portion 136 smoothly secures the weaving endingportion of the weaving wire 116.

After constructing the wound coil 100 in which the weaving wire 116 isthus woven around the outer peripheral surfaces of the upper and lowerplates 102 and 104, the wound coil 100 is taken out by separating theupper jig 12 from the lower jig 14 by the elevation mechanism not shownand is conveyed to the next process.

Thus, according to the present embodiment, the wound coil 100 composedof the bobbinless coil may be formed readily and efficiently by holdingthe upper and lower plates 102 and 104 disposed separately by thepredetermined distance by the upper and lower jigs 12 and 14 and bywinding the wire rod 106 around the peripheral surface of the clawsection 240 provided in the lower jig 14 (see a block E in FIG. 30).

Further, according to the present embodiment, the isolation quality ofthe stacked coil 108 may be steadily secured by winding the windingbeginning and ending portions of the stacked coil 108 exposed to theoutside respectively to the first and second winding securing sections110 a and 110 b separated in the left and right directions and bydrawing those portions in cross by separating to the upper and lowersurfaces of the plate portion 124, in addition to that the isolationquality of the stacked coil 108 arrayed between the upper and lowerplates 102 and 104 is suitably maintained.

In other words, the present embodiment allows the isolation quality tobe steadily maintained by drawing the winding beginning portion of thestacked coil 108 along the under surface 104 b of the plate portion 124of the lower plate 104 made of resin via the second guide groove 126, bydrawing the winding ending portion of the stacked coil 108 so as tocross with the winding beginning portion along the upper surface 104 aof the plate portion 124 of the lower plate 104 and by interposing theplate portion 124 made of a resin material between the winding beginningportion and the winding ending portion to keep a non-contact state.

While one embodiment of the invention has been described above, theinvention is not limited to the embodiment described above and may bemodified within a scope of the gist of the invention as follows forexample.

Although the claw section 240 has been arranged to have the firstthrough third split claws 241 a through 241 c in the embodimentdescribed above, the number of split claws is not limited to be threeand may be two or four or more. Still more, the number of the radialsprings 251 and the thrust springs 265 may be adequately changed.

Although the arrangement in which the thrust spring 265 is a compressioncoil spring has been exemplified in the embodiment described above, itmay be a rubber material formed by adequate rubber for example. The sameapplies also to the radial spring 251.

Although the upper jig 12 has been provided with the tapered portion 220and the lower jig 14 has been provided with the claw section 240 in theembodiment described above, the function of the upper jig 12 may bereversed with the function of the lower jig 14. That is, the upper jig12 may be provided with the claw section 240 and the lower jig 14 may beprovided with the tapered portion 220.

Next, a process of acquiring the molded coil by molding the wound coil100 formed in the previously described process with the resin materialwill be explained below. FIG. 23 is a schematic structural longitudinalsection view of the die assembly for molding the wound coil and FIG. 24is a schematic structural longitudinal section view of the die assemblyshown in FIG. 23 that is clamped after loading the form-to-be-moldedinto a cavity of the assembly.

First, the coil-to-be-molded 300 whose outer surface, except of itsinner surface, is to be coated (molded) by the resin material will beexplained. As shown in FIG. 29A, the coil-to-be-molded 300 has the woundcoil 100 sandwiched between the first plate (the lower plate) 104 on anupper side in the figure and the second plate (the upper plate) 102 on alower side in the figure respectively made of the resin material andhaving the coil stacked by the wire rod 106 into the plurality oflevels, a terminal section 150 connected with the pair of windingsecuring sections 110 a and 110 b protruding in the radial outwarddirection of the first plate 104 and is electrically connected with thecoil and the weaving wire 116 for holding the first and second plates104 and 102 by weaving the circular arc projections 114 a and 114 b ofthe first and second plates 104 and the second plate 102 disposeddistant by the predetermined distance in the vertical direction.

It is noted that the coil-to-be-molded 300 is arranged such that thelower plate 104 composing the wound coil 100 shown in FIG. 1 becomes thefirst plate 104 on the upper side and the upper plate 102 becomes thesecond plate 102 on the lower side. That is, the coil-to-be-molded 300is disposed such that the wound coil 100 is vertically turned over.Beside them, the same or corresponding structural elements will beexplained below by denoting the same reference numerals.

The terminal section 150 has a terminal 152 a electrically connectedwith the winding beginning portion of the wire rod 106 and a terminal152 b electrically connected with the winding ending portion of the wirerod 106. Still more, no core material such as a coil bobbin is providedin the coil inner peripheral surface 120 of the wound coil 100 and thecoil inner peripheral surface 120 is exposed to the outside.

The first plate 104 is provided with three projections 154 that projectby a predetermined length in the radial outward direction from the coilouter peripheral surface 121 (see FIG. 23) and are distant equiangularlyalong the peripheral direction between the neighboring circular arcprojections 114 b. As shown in FIG. 28, each of these projections 154functions as a molten resin receiving section positioned right under aterminal portion of each gate when the molten resin is injected into acavity 430 from a plurality of gates of an upper die 412 as describedbelow and promotes a flow of the molten resin so that the molten resinreceived by the projection 154 is filled into a thin portion moldingairspace 444 described below.

As shown in FIG. 23, the die assembly 410 includes the upper die 412liftably provided by a elevation mechanism not shown, a lower die 414fixed on a base not shown and a pair of split dies 420 a and 420 bmovably provided in the horizontal direction through a displacementmechanism not shown and provided with a projection that functions as anesting for forming a hollow coupler section 502 described later (seeFIG. 29B). It is noted that the pair of split dies 420 a and 420 b maybe constructed in a body without splitting them.

Still more, the die assembly 410 has a first die member 424 fitted intoa hole of the upper die 412 and having a ringed projection 422 bulginglyformed to butt the upper surface in a vicinity of an inner peripheraledge portion of the first plate 104 on the upper side and to press andseal the wound coil 100 downward, a second die member 428 fitted into ahole of the lower die 414 and having a ringed projection 426 bulginglyformed so as to face the under surface of the second plate 102 on thelower side to form a ringed groove (not shown) for seal-fitting to abottom surface of the molded resin 500 (see FIG. 29B) and a core member432 fitted into the second die member 428 for forming a cavity 430between wall surfaces of the upper and lower dies 412 and 414 (see FIG.24). It is noted that the die assembly 410 is provided with a degassingpassage not shown communicating with the cavity 430.

The upper die 412 is provided with a plurality of gates connected to amolten resin supplier not shown including a plastic injection moldingmachine for example to discharge (inject) the molten resin to the cavity430. As shown in FIG. 27, the plurality of gates is disposed by beingseparated equiangularly in the peripheral direction of the wound coil100 and includes first through third gates 434 a through 434 c that forma sealing resin 504 (see FIG. 29B) that coats the outer peripheralsurface and the both end surfaces in the axial direction of the woundcoil 100 and a fourth gate 434 d that forms the coupler section 502formed of a housing storing the first and second terminals 152 a and 152b.

Here, the first through third gates 434 a through 434 c are disposed atpositions corresponding to the projections 154 of the upper die 412i.e., right above or substantially right above the projections 154, whenthe dies are clamped as shown in FIGS. 24 and 27. It is noted that FIG.27 is a plan view of the clamped die assembly 410 when seen from aboveand shows the projections 154 of the first plate 104 disposed within thecavity 430 by solid lines for convenience to clarify the positionalrelationship in the vertical direction between the first through thirdgates 434 a through 434 c and the projections 154 of the first plate104.

The lower die 414 is provided with a plurality of ejector pins 436 (seeFIG. 26) for taking out the molded resin 500 out of the cavity 430 bypressing the molded resin 500 whose molten resin is solidified upward.The ejector pins 436 are provided so as to be displaceable in thevertical direction by a driving action of an actuator not shown.

As shown in FIG. 23, the core member 432 is provided with a columnarsection 438 that contacts the inner peripheral surface 160 of the firstplate 104 and performs positioning and sealing functions with the innerperipheral surface 160 of the first plate 104, a broad base portion 440composed of a ringed enlarged portion that contacts the inner peripheralsurface 162 of the second plate 102 and performs positioning and sealingfunctions with the inner peripheral surface 162 of the second plate 102and a ringed stepped portion 439 formed closely to the second die member428 under the broad base portion 440 to press the under surface in thevicinity of the curved portion of the second plate 102 upward.

A diameter (outer diameter) D1 of the columnar section 438 of the coremember 432 that faces to the coil inner peripheral surface 120 betweenthe first plate 104 and the second plate 102 in the vertical directionis set to be smaller than an inner diameter D2 of the coil innerperipheral surface 120 (D1<D2). Accordingly, when the coil-to-be-molded300 is loaded into the cavity 430 and the die assembly is clamed, thecore member 432 is kept in a non-contact state with the coil and aclearance 442 is created between the outer peripheral surface of thecolumnar section 438 of the core member 432 and the coil innerperipheral surface 120 as shown in FIG. 24.

It is noted that although the upper die 412 is provided liftably withrespect to the lower die 414 in the present embodiment, the invention isnot limited to that and it will do if the upper die 412 and the lowerdie 414 are provided relatively separably.

The die assembly 410 for carrying out the molding is constructedbasically as described above. Next, its actions and effects will beexplained.

At first, after loading the coil-to-be-molded 300 (see FIG. 29A) intothe cavity 430 of the die assembly 410, the upper die 412 and the firstdie member 424 are lowered in a body by means of the elevation mechanismnot shown and the pair of split dies 420 a and 420 b are displaced bythe displacement mechanism not shown to clamp the die assembly as shownin FIG. 23.

In the clamped state, the terminal portions 446 of the first throughthird gates 434 a through 434 c are positioned so as to correspond tothe projections 154 of the first plate 104 in the vertical direction.That is, the terminal portions 446 of the first through third gates 434a through 434 c come at the positions right above or substantially rightabove the projections 154. Still more, in the clamped state describedabove, the ringed airspace for molding thin portion 444 whose verticalsize is small and radial size is narrow is formed between a bottom wallof the upper die 412 and the upper surface of the first plate 104. It isnoted that the thin portion molding airspace 444 composes a part of thecavity 430 and forms a thin portion 512 that composes a bottom surfaceof a ringed concave portion 506 formed on an outer end surface (uppersurface) of the molded resin 500 described later.

After claming the dies, the molten resin supplying source not shown isurged to inject the molten resin from the first through fourth gates 434a through 434 d (see FIG. 25). The molten resin discharged out of theterminal portions 446 of the first through third gates 434 a through 434c is received by the projections 154 of the first plate 104 thatfunction as the molten resin receiving sections, is promoted to flowinto and to smoothly fill the thin portion molding airspace 444 formedbetween the bottom wall of the upper die 412 and the upper surface ofthe first plate 104 and is also flown downward along the cavity 430formed between the outer peripheral surface of the coil-to-be-molded 300and the side wall of the lower die 414 (see FIG. 28). It is noted that adirection in which the molten resin is filled is supposed to be parallelwith the axial direction of the wound coil 100 and to be graduallyfilled from the lower part to the upper part of the cavity 430.

In other words, if no projection 154 is provided right under theterminal portions 446 of the first through third gates 434 a through 434c, there is nothing that receives the molten resin discharged out of theterminal portions 446 of the first through third gates 434 a through 434c, so that the molten resin flows only downward along the cavity 430.Accordingly, the molten resin hardly flows into the thin portion moldingairspace 444 that extends in the horizontal direction (the directionorthogonal to the discharge direction of the molten resin) from theterminal portions 446 of the first through third gates 434 a through 434c and there is a possibility of causing short molding due to aninsufficient amount of the molten resin to be filled into the thinportion molding airspace 444.

However, because the projection 154 that functions as the molten resinreceiving section is provided so as to project by the predeterminedlength in the radial outward direction at the outer periphery of thefirst plate 104 so that it is positioned right under each of the firstthrough third gates 434 a through 434 c and the projection 154 changesthe flow direction of the molten resin such that the molten resin canflow in the horizontal direction from the terminal portion 446 of eachgate, the present embodiment can suitably prevent the short moldingdescribed above from occurring by smoothly filling the molten resin intothe thin portion molding airspace 444.

At this time, the ringed projection 422 of the first die member 424butts the upper surface near the inner peripheral portion of the firstplate 104 and presses down the coil-to-be-molded 300, so that it maysuitably prevents such a phenomena that the first and second plates 104and 102 are lifted up from otherwise occurring when the molten resin isfilled along the cavity 430.

Further, the inner peripheral surface 160 of the first plate 104contacts the outer peripheral surface of the columnar section 438 of thecore member 432, thus forming a first sealing section, and the innerperipheral surface 162 of the second plate 102 contacts the broad baseportion 440 of the core member 432, thus forming a second sealingsection. Still more, because the first plate 104 on the upper side andthe second plate 102 on the lower side are positioned respectively atpredetermined positions by the columnar section 438 and the broad baseportion 440 of the core member 432, coaxiality (coaxial precision) ofthe coil-to-be-molded 300 is improved. Accordingly, when the moltenresin is filled along the cavity 430, the first and second sealingsections formed by the inner peripheral surfaces 160 and 162 of thefirst and second plates 104 and 102 suitably prevent the molten resinfrom entering the coil inner peripheral surface 120 and allow the moltenresin to be filled favorably into the coil-to-be-molded 300 whileassuring the coaxiality.

Still more, the clearance 442 is formed between the outer peripheralsurface of the columnar section 438 of the core member 432 and the coilinner peripheral surface 120 as described above. As a result, the wirerod 106 stacked on the coil inner peripheral surface 120 is suitablyprotected without being damaged in loading into the cavity 430 or by theflow of the molten resin.

The sealing function may be improved further in the present embodimentin cooperation with the sealing action of the first sealing section byproviding the first die member 424 having the ringed projection 422 thatpresses down the vicinity of the inner peripheral surface of the firstplate 104. The sealing function may be also improved further in thepresent embodiment in cooperation with the sealing action of the secondsealing section by providing the ringed stepped portion 439 that pressesup the under surface in the vicinity of the bend portion of the secondplate 102 in the core member 432.

When the molten resin is solidified after competing the injection of themolten resin into the cavity 430 from the first through fourth gates 434a through 434 d, the molded resin (molded coil) 500 in which the bothend surfaces in the axial direction and the outer peripheral surface ofthe wound coil 100, except of the coil inner peripheral surface 120, aremolded by the resin material is formed (see a block E3 in FIG. 30).Then, the molded resin 500 may be readily taken out of the cavity 430 ofthe die assembly 410 and may be transferred to a next step by raisingthe plurality of ejector pins 436 under the driving action of theactuator not shown and by pressing the molded resin 500 upward.

As shown in FIG. 29B, the molded resin 500 is provided, at the uppersurface thereof (the outer end surface along the axial direction), witha ringed concave portion 506 formed so as to attach a sealing member notshown and a plurality of traces of gates 510 having substantially ashape of a small circle are formed on a ringed convex edge portion 508located in the radial outward direction from the ringed concave portion506. Accordingly, no gate trace is formed within the ringed concaveportion 506 that becomes the sealing surface, so that the sealingsurface composed of a flat surface having no irregularity exhibits thesealing function suitably.

In other words, the traces of gates 510 are formed on the outerperipheral side of the thin portion 512 of the molded resin 500 formedby the thin portion molding airspace 444 by disposing The first throughthird gates 434 a through 4343 in the radial outward direction more thanthe thin portion molding airspace 444. Accordingly, because no traces510 are formed on the thin portion 512 that becomes the sealing surface,the sealing surface composed of the flat surface having no irregularityexhibits the sealing function suitably.

Still more, the thin portion 512 composing the bottom surface of theringed concave portion 506 is formed on the outer side surface along theaxial direction of the molded resin 500. The thin portion 512 is formedby the molten resin filled into the thin portion molding airspace 444that is a part of the cavity 430 is solidified, so that a good moldedsurface may be formed from which any short molding and sink are suitablyprevented as described above.

It is noted that although the mode described above is the best mode forcarrying out the invention, it is not intended to limit the invention tosuch mode. Accordingly, the mode for carrying out the invention may bevariously modified within a scope in which the subject matter of theinvention is not changed.

What is claimed is:
 1. A coil winding method for forming a stacked coilby winding a wire rod supplied from a nozzle to a claw section providedbetween upper and lower plates, wherein an upper jig to which the upperplate is attached is coaxially joined with a lower jig to which thelower plate is attached and the upper and lower jigs are supported so asto be integrally rotated in a predetermined direction, comprising stepsof: drawing the wire rod along a guide groove formed on an under surfaceof the lower plate after securing a winding beginning portion of thewire rod by a first winding securing section of the lower plate; formingthe stacked coil by winding the wire rod around the peripheral surfaceof the claw section after drawing the wire rod from an outer peripheralportion of the lower plate to an inner peripheral portion thereof byexposing the wire rod from an under surface of the lower plate to anupper surface thereof; and securing a winding ending portion of the wirerod to a second winding securing section of the lower plate afterdrawing the wire rod from the inner peripheral portion to the outerperipheral portion along the upper surface of the lower plate; whereinthe winding beginning portion of the wire rod secured to the firstwinding securing section and the winding ending portion of the wire rodsecured to the second winding securing section are disposed so as tocross from each other at the upper and under surfaces of the lowerplate.
 2. The coil winding method as set forth in claim 1, wherein aplurality of projections that project in the radial outward direction isprovided around the outer peripheral portion of the upper plate, aplurality of projections that project in the radial outward direction isprovided around the outer peripheral portion of the lower plate, theprojections of the upper and lower plates are disposed so as not to bevertically superimposed, the projections of the upper plate and theprojections of the lower plate are woven alternately along a peripheraldirection by a weaving wire after securing the winding ending portion ofthe wire rod to the second winding securing section of the lower plate.3. The coil winding method as set forth in claim 1, wherein the clawsection is composed of a plurality of split claws and at least one splitclaw has a groove formed so as to guide the wire rod along theperipheral direction.